1. Field of the Invention
This invention relates to an oil brake device for bicycles and more particularly to an oil brake device for bicycles to make the saddle frame temporarily immovable with respect to the main body frame.
2. Prior Art
The present applicant previously made public Japanese patent publication No. 580/1979, U.S. Pat. No. 4,118,045, British Pat. No. 1557262 and Japanese Utility Model Publication No. 53240/1978 concerning bicycles in which such a floating frame unit was separated from the main body frame and resiliently suspended thereon. This invention is intended to provide a bicycle which is improved in safety and in comfortable ride over those previous inventions. A description will now be given both of the structure and disadvantages of the bicycles that have afforded a basis for this invention and of the construction of the invention.
In the bicycle disclosed in Japanese Patent Publication No. 580/1979, U.S. Pat. No. 4,118,045 and British Pat. No. 1557262, as shown in FIG. 1, a floating frame unit 20 comprises a saddle support 14 and a horizontal member 15 both secured to the unit 14; said support having a saddle 12 at the upper end and a rear wheel driving gear means 16 at the lower end thereof, said member having forked portions 6 and 6' at the front end thereof, said portions being formed integrally with upward bent portions 9 and 9' having sub-handles 10 and 10' rotatably mounted thereto, said sub-handles having handle insertions tubes 171 and 171' secured thereto. The floating frame unit is constructed independent of a main body frame 21 made up integrally of upper forked portions 7 and 7' and lower forked portions 8 and 8', upper and lower horizontal bars 5 and 5' and a handle insertion tube 19. The upper forked portions 7 and 7' are connected through spring means 13 and 13' to arms 11 and 11' projecting from the saddle support 14 and an upper horizontal bar 5' is at its intermediate point 151 connected through a spring means 150 to the saddle support 14. Furthermore, a point 14' on the lower horizontal bar 5 is rotatably connected by a link 153 to a point 152 on the saddle support 14. Accordingly, the floating frame unit 20 is resiliently suspended independent of the main body frame 21 and is permitted not only to make independent vertical movement but also swing back and forth with the point 152 as a center. A handle bar 2 is inserted into the handle insertion tube 19 and is provided at the lower end with a front wheel 1 and formed integrally with the main body frame 21. To the sub-handles 10 and 10' which form part of the floating frame unit 20 are secured handle insertion tubes 171 and 171' each on the left and right, and the ends of a lever 4 pass respectively through the insertion portions 170 and 170' of the handle insertion tubes. Accordingly, when the sub-handles 10 and 10' are moved with the upward bent portions 9 and 9' forming the center of rotation of the sub-handles as a center, the handle lever 4 passing through the handle insertion tubes 171 and 171' formed integrally with the sub-handles are also moved around the handle bar 2 and consequently a front wheel 1 connected to the lower end of the handle bar 2 is rotated to change the direction of movement of a cycle.
Referring now to the bicycle which is disclosed in Japanese Utility Model Publication No. 53240/1978, the bicycle therein dispenses with the handles 10 and 10' and handle insertion tubes 171 and 171', horizontal bar 15, forked portions 6 and 6', upward bent portions 9 and 9' which are used in the bicycle disclosed in the preceding invention in Japanese patent publication No. 580/1979, shown in FIG. 1. The handle 4 is controlled directly by hand in the same manner as that of the bicycle generally used.
In the bicycle of the kind described above, the saddle support 14 is independent of the main body frame 21 and resiliently suspended on the frame 21 by spring means 13 and 13', and accordingly when a rider rests his weight on the saddle, the whole of the saddle support is lowered but when he rests one foot on the ground so as to stop the bicycle for example on the red traffic light, the body weight resting on the saddle support is decreased as that much and the saddle support is elevated. When the rider restarts in such an unstable state, he feels it difficult to poise himself, which is dangerous for the rider. The present inventor therefore manufactured on an experimental basis a device for applying the brake to the wheel of a bicycle and simultaneously to the saddle support so as to prevent the saddle support from being elevated when the bicycle is stopped. The inventor made various experiments on the device and completed a mechanical brake and filed Japanese Utility Model Application No. 18797/1977 for the brake. Later on, the Applicant found the following drawbacks in the brake. Namely, application of the brake with respect to the saddle support is effected by the control of the brake lever mounted to the handle, but the mechanical brake makes it necessary to use an exceedingly great amount of force for simply braking the saddle support. Secondly, the force applied to the brake lever is dividedly imparted to the saddle support brake and wheel brake, with the result that the wheel brake is reduced in working. Thirdly, provision of independent brake levers for the saddle support and the wheel complicate brake manipulation, which invites increased danger. Such are the drawbacks. In order to obviate such disadvantages, various improvements have been made and consequently the oil brake device proposed in the present application has been found free from the disadvantages.